Option 1. Install a Greek and Hebrew keyboard in Windows

To change between keyboards once they’re installed, the default Windows hotkey is Left Alt + Shift. This hotkey can be changed, and individual hotkeys can be assigned to each keyboard by going to: Control Panels -> Region and Language -> Keyboards and Languages -> Change Keyboards -> Advanced Key Settings (different in Windows 10).

In Windows 7 there is also a button in the taskbar to switch between languages, on an English language system it will be a small EN by default. This may have been turned off, but can be enabled by right-clicking on the taskbar -> Toolbars -> Language bar.

This method has the advantage that because it is at the OS level, you can enter greek and hebrew text in the same way into any program; and there are also keyboards available for numerous other languages.

Option 2. Type it in via transliteration by starting with g: or h:

You can essentially type phonetically; or by using any accepted transliteration scheme, and you will be given a list of Hebrew or Greek words to choose from e.g. g:agape, h:elohim